refactor async io, add in_isr argument to tud_msc_async_io_done()

use cbw.command[0] for pending IO command

src/class/msc/msc_device.h

@@ -49,10 +49,11 @@
 #endif
 
 // Return value of callback functions
-// Error
-#define TUD_MSC_RET_ERROR  -1
-// Asynchronous IO
-#define TUD_MSC_RET_ASYNC  -16
+enum {
+  TUD_MSC_RET_BUSY = 0,   // Busy, e.g disk I/O is not ready
+  TUD_MSC_RET_ERROR = -1,
+  TUD_MSC_RET_ASYNC = -2, // Asynchronous IO
+};
 
 TU_VERIFY_STATIC(CFG_TUD_MSC_EP_BUFSIZE < UINT16_MAX, "Size is not correct");
 
@@ -63,54 +64,31 @@ TU_VERIFY_STATIC(CFG_TUD_MSC_EP_BUFSIZE < UINT16_MAX, "Size is not correct");
 // Set SCSI sense response
 bool tud_msc_set_sense(uint8_t lun, uint8_t sense_key, uint8_t add_sense_code, uint8_t add_sense_qualifier);
 
-// Called once asynchronous read/write operation is done
-// bytes_processed has the same meaning of tud_msc_read10_cb() /
-// tud_msc_write10_cb() return value
-void tud_msc_async_io_done(int32_t bytes_processed);
+// Called by Application once asynchronous I/O operation is done
+// bytes_io is number of bytes in I/O op, typically the bufsize in read/write_cb() or
+// TUD_MSC_RET_ERROR (-1) for error. Note TUD_MSC_RET_BUSY (0) will be treated as error as well.
+bool tud_msc_async_io_done(int32_t bytes_io, bool in_isr);
 
 //--------------------------------------------------------------------+
 // Application Callbacks (WEAK is optional)
 //--------------------------------------------------------------------+
 
-// Invoked when received SCSI READ10 command
-// - Address = lba * BLOCK_SIZE + offset
-//   - offset is only needed if CFG_TUD_MSC_EP_BUFSIZE is smaller than BLOCK_SIZE.
-//
-// - Application fill the buffer (up to bufsize) with address contents and return number of bytes read or status.
-//
-//   - ret < bufsize  : These bytes are transferred first and callback will be invoked again for remaining data.
-//
-//   - ret == 0       : Indicate application is not ready yet e.g disk I/O busy.
-//                      Callback will be invoked again with the same parameters later on.
-//
-//   - ret == TUD_MSC_RET_ERROR (-1)
-//                    : Indicate application error e.g invalid address. This request will be STALLed
-//                      and return failed status in command status wrapper phase.
-//
-//   - ret == TUD_MSC_RET_ASYNC (-16)
-//                    : Data reading will be done asynchronously in a background task. Application should return immediately.
-//                      tud_msc_async_io_done() must be called once reading is done to signal completion.
+/*
+  Invoked when received SCSI READ10/WRITE10 command
+  - Address = lba * BLOCK_SIZE + offset
+    - offset is only needed if CFG_TUD_MSC_EP_BUFSIZE is smaller than BLOCK_SIZE.
+  - Application fill the buffer (up to bufsize) with address contents and return number of bytes read or status.
+    - 0 < ret < bufsize: These bytes are transferred first and callback will be invoked again for remaining data.
+    - ret == TUD_MSC_RET_BUSY
+        Application is buys e.g disk I/O not ready.
+        Callback will be invoked again with the same parameters later on.
+    - ret == TUD_MSC_RET_ERROR
+        error such as invalid address. This request will be STALLed and scsi command will be failed
+    - ret == TUD_MSC_RET_ASYNC
+        Data I/O will be done asynchronously in a background task. Application should return immediately.
+        tud_msc_async_io_done() must be called once IO/ is done to signal completion.
+*/
 int32_t tud_msc_read10_cb (uint8_t lun, uint32_t lba, uint32_t offset, void* buffer, uint32_t bufsize);
-
-// Invoked when received SCSI WRITE10 command
-// - Address = lba * BLOCK_SIZE + offset
-//   - offset is only needed if CFG_TUD_MSC_EP_BUFSIZE is smaller than BLOCK_SIZE.
-//
-// - Application writes data from buffer to address contents (up to bufsize) and returns the number of bytes written or status.
-//
-//   - ret < bufsize  : Callback will be invoked again with remaining data later on.
-//
-//   - ret == 0       : Indicate application is not ready yet e.g disk I/O busy.
-//                      Callback will be invoked again with the same parameters later on.
-//
-//   - ret == TUD_MSC_RET_ERROR (-1)
-//                    : Indicate application error e.g invalid address. This request will be STALLed
-//                      and return failed status in command status wrapper phase.
-//
-//   - ret == TUD_MSC_RET_ASYNC (-16)
-//                    : Data writing will be done asynchronously in a background task. Application should return immediately.
-//                      tud_msc_async_io_done() must be called once writing is done to signal completion.
-// TODO change buffer to const uint8_t*
 int32_t tud_msc_write10_cb (uint8_t lun, uint32_t lba, uint32_t offset, uint8_t* buffer, uint32_t bufsize);
 
 // Invoked when received SCSI_CMD_INQUIRY